>> i would imagine something huge you would need something more than a small box, you would have robotic arms that go on and on and on? i read that down at usc they're printing a building. >> yes, there is a guy down at usc, a professor who printed a building. enormous robotic structure computer controlled, he basically instead of the plastic that this is made out of, made it out of concrete. no forms. you're not pouring concrete into forms like you would in a tradition thing. it's going around layer by layer building up a building. >> the only limitation is imagination? >> yes, in some ways there is always the limit of imagination. there are practical limitations of how much it costs, how long does it take, those are real considerations, but one of the things about most technology, and this is following the same trajectory as you watch over time prices are coming down.